Parkinson's disease (PD) is a neurologically disabling, idiopathic CNS degenerative disorder whose progression would be desirable to slow or stop by neuroprotective treatment. To reach this overall goal, medications and other treatments will be identified and scientifically tested by PD Centers participating in this NINDS initiative. The initial goal of the NINDS project is to identify Centers that will enroll patients with early PD. As a proposed PD Center, we at Henry Ford Health System (HFHS) will fulfill the following specific aims: 1. to ascertain, recruit and enroll at least two new PD cases, at Hoehn-Yahr stage 2 or less, each month for at least 36 months; 2. to characterize enrolled PD cases motorically, 12 hours off current anti-PD medications, by their Hoehn-Yahr stage, Unified Parkinson's Disease Rating Scale scores, and simple/choice reaction and movement times; 3. to characterize enrolled PD cases cognitively by age-and education- adjusted Mini-Mental State Examination (MMSE) scores; 4. to consider enrolled PD cases for inclusion in possible future brain positron emission tomographic (PET) studies in collaboration with colleagues at the University of Michigan.